Method of driving spindles of textile machines

ABSTRACT

A method of driving spindles of a textile machine of the type which has a plurality of yarn delivery stations and a winding station spindle pair associated with each yarn delivery station is provided. Each spindle is provided with its own variable rpm drive motor. During any operational period one spindle of the pair acts as the winding spindle on which a yarn package is being formed, while the other spindle of the same pair acts as an idling spindle. The role of the two spindles is exchanged upon redirecting the yarn from one spindle to the other. In order to have that spindle which is functioning as the idling spindle ready to take over the winding function during all operational periods so as to take over the winding function at any time the yarn breaks during winding on the other spindle, the idling spindle is driven at a maximum given standby rpm during all operational periods.

United States Patent 11 1 Wolf [ 1 a May 20,1975

[ METHOD OF DRIVING SPINDLES OF TEXTILE MACHINES [75] Inventor: Horst Wolf, Albershausen, Germany [73] Assignee: Zinser-Textilmaschinen Gesellschaft,

Ebersbach, Germany [22] Filed: Oct. 23, I973 [21] Appl. No.: 408,999

Related U.S. Application Data [63] Continuation-in-part of Ser. No. 266,478, June 26, 1972, abandoned, which is a continuation of Ser. No. 82,774, Oct. 21, 1970, abandoned.

[30] Foreign Application Priority Data Oct. 2l, 1969 Germany 1952909 [52] U.S. Cl. 57/156; 57/92; 57/93; 57/100; 242/18 A [51] Int. Cl D0lh 1/26 [58] Field of Search 57/156, 92, 93, 100; 242/18 A, 18 R [56] References Cited UNITED STATES PATENTS 3,550,871 12/1970 Keith 242/18 A Primary Examiner-John Petrakes Attorney, Agent, or Firm-Edwin E. Greigg ABSTRACT A method of driving spindles of atextile machine of the type which has a pluralityof yarn delivery stations and a winding station spindle pair associated with each yarn delivery station is provided. Each spindle is provided with its own variable rpm drive motor. During any operational period one spindle of the pair acts as the winding spindle on which a yarn package is being formed, while the other spindle of the same pair acts as an idling spindle. The role of the two spindles is exchanged upon redirecting the yarn from one spindle to the other. In order to have that spindle which is functioning as the idling spindle ready to take over the winding function during all operational periods so as to take over the winding function at any time the yarn breaks during winding on the other spindle, the idling spindle is driven at a maximum given standby rpm during all operational periods.

1 Claim, 3 Drawing Figures METHOD OF DRIVING SPINDLES OF TEXTILE MACHINES REFERENCE TO RELATED APPLICATIONS This application is a continuatiomin-part of the copending application Ser. No. 266,478 of Horst Wolf entitled Driving System for Spindles of Textile Machines filed on June 26, 1972 now abandoned. The application Ser. NO. 266,478 is a continuation of the application Ser. No. 82,774 of Horst Wolf entitled Driving System for Spindles of Textile Machines tiled on Oct. 21, 1970 now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a method of driving a plurality of spindles forming part of a textile machine and serving for the winding of yarns on spools supported by the spindles. Preferably, the machine is a spinning or twisting machine for endless yarns wherein each spindle has its own drive motor. The rpm of each drive motor is at a maximum when winding on an empty spool is started and is decreased at least during a part of the winding period. I

In textile machines of this type, for example, in spirining machines, draw-twisting machines, or the like, the yarns, after submitted to drawing or similar treatment, are wound on the spools which are inserted on the spindles. During such winding the yarns are twisted. It is known and advantageous to decrease the spindle rpm at least during a portion of the winding period as the diameter of the wound package increases.

In some cases it is desired or even required that the spindle rpms be variable at any time independently from one another, for example, as a function of the yarn tension or other variables. In this connection difficulties are encountered because of the relatively large number of spindles (cg, 100 300) in such machines and because the spindle rpms should be variable in a large range, for example, in a ratio of 1:10. i

This invention is particularly concerned with a method to be practiced in textile machines of the known type in which with each yarn delivery station there is associated a winding station pair, each having a separate spindle with its own variable rpm drive motor. At any time, winding occurs on one spindle, while, at the same time, the other spindle is idle. When a new yarn package is started, the two spindles exchange roles. H

According to the conventional method practiced in the above-outlined apparatuses, just prior to the start ofa new yarn package, the heretofore stationary idling spindle is set into motion and brought to the standby rpm by the time the feeding of the yarn is to be switched over to the idling spindle.

The afore-outlined method is disadvantageous for maintaining a substantially uninterrupted winding operation in case of yarn breakage. Upon such an occur rence the stationary idling spindle, on which the winding was to continue, had to be first brought to the standby rpm.'This has resulted in a delay adversely affecting the winding operation and its efficiency.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide an improved method of driving spindles of textile machines in which delay in transfering the winding function from one spindle to another spindle of a pair is avoided even upon the occurrence of yarn breakage.

The above mentioned object, as well as others which are to be made clear from the text below, is accomplished in a method of driving spindles of a textile machine of the type which has a plurality of yarn delivery stations and a winding station spindle pair associated with each yarn delivery station. Each spindle has its own variable rpm drive motor. During any operational period one spindle of the pair functions as the winding spindle on which a yarn package is being formed, while simultaneously the other spindle of the same pair functions as the idling spindle. The role of the two spindles isexchanged upon redirecting the yarn from one spindle to the other. The salient feature of the method is the step of driving the idling spindle at a maximum given standby rpm during all operatingtimes for the purpose of allowing the idling spindle to take over the winding function upon the occurrence of yarn breakages during winding on the other spindle of the pair.

The winding spindle is driven with a decreasing rpm as a function of winding parameters. I

BRIEF DESCRIPTION OF THE DRAWING 'FIG. 1 is a schematic side elevational view of a draw- DESCRlPTlON oFTHE EMBODIMENT Turning now to FIG. 1, there is shown a drawtwisting machine which, may include a great number (e.g., -100) of drawing devices 10 (only one shown).

The outlet of the drawing device 10 forms a yarn deliv-.

ery station 11 with which there'are associated two winding stations 12 and 13. Upstream of the drawing device 10 there is disposed a spool support 14 for carrying a spool 15 on which there is wound an untreated,

endless, synthetic yarn to be stretched in the drawtwisting machine three to four times its original length and to be provided with an initial slight protective twist. The yarn 15' taken from the spool 15 first passes through a yarn guide 16 and thereafter is trained about two godets 17 and 18. From the latter the yarn enters a drawing zone 19 in which it is submitted to a drawing operation under the application of heat from a hot plate 20. From the drawing zone 19 the yarn is taken by a godet 21 with constant speed and is directed through a yarn tension meter 22. Thereafter, the yarn enters a first yarn channel 23 and then a deflector head 24. The latter directs the yarn 15' in a selective manner into a yarn outlet channel 25 or 26 for guiding the yarn either to the yarn winding station 12 or to the yarn winding station 13. The two yarn winding stations.l2 and 13 are of identical structure and have a driven bell 30 (30') and a spindle 33 (33') which is driven by an asynchronous, variable rpm drive motor 31 (31') and which is reciprocable vertically by means of a hydraulic assembly 32 (32'). Each asynchronous drive motor may be a three-phase squirrel cage motor or a twophase system motor, or a one-phase condenser motor or any other asynchronous motor, the line frequencydependent rpm of which may be varied by a thyristor setting member. Each spindle is associated with a brake for manually arresting its rotation.

The godets 17, 18 and 21 are driven by a common motor 35. The bells 30, are driven with a constant rpm by a common drive belt 36 from a motor, not shown, preferably in a direction opposite to the rotation of spindles 33, 33'. In FIG. 1 the spindles 33, 33'

are in their lowest positions in which no winding of yarn takes place. During operation, on .the other hand, at all times at least one spindle is in such a position that the spool supported thereon is capable of receiving yarn; in such a position the spool projects into the inner space of the bell, When a spool is fully wound (a condition which is shown for the left hand spool 34), it is brought into its lowest position by moving the spindle downwardly. In that position, an empty spindle may be substituted for the spindle containing a fully wound package. As soon as the other spool is fully wound, it is replaced by an empty spool. Each time a yarn package is completed on a spool or yarn breakage occurs, the yarn, by means of the deflector head 24, is redirected from the yarn outlet channel used theretofore into another yarn outlet channel with the simultaneous severing of the yarn if no free yarn end yet exists. The newly activated yarn outlet channel is associated with the yarn winding station which at that moment has an empty spool. In this manner, the yarn may be alternately guided without interruption to the yarn winding stations 12 and 13. i

Each yarn outlet channel 25, 26 extends from the deflector head 24 through a rotary coupling (not shown) to the vicinity of the lowest location of the associated bell 30', 30, respectively. The outlet opening 27 of each outlet channel is arranged horizontally and tangentially with respect to the empty spool associated therewith. In this manner it is possible to direct the yarn, by means of air pressure passing through the yarn channel 23, the deflector head 24 and the yarn outlet channel 25 or 26, onto the empty spool in such a manner that it is automatically picked up thereby by virtue of its rotation.

Downstream of the yarn tension meter 22, the yarn passes in succession through two air blow nozzles 37, 38 which have a structure similar to water jet pumps. In the structure illustrated, pressurized air is admitted to the first nozzle 37 through a conduit 39 and is directed downwardly through yarn channel 23. Thereaf- I nozzle 38 which also receives pressurized air from a conduit 40. The second nozzle 38 guides the pressurized air admitted thereto in a selective manner into either the yarn outlet channel 25 or 26, dependent upon the position of a mechanically operated plug-like deflector member of the deflector head 24.

The structure of the individual yarn winding stations 12 and 13 corresponds in principle to that described in German published application (Offenlegungsschrift) No. 1,453,534 which describes an apparatus for winding yarns. In the present case the yarn tension of the yarn to be wound is regulated to maintain a constant value. The yarn tension is controlled by affecting the rpm of the individual spindle drive motors 31, 31' by means of a regulator 44 (FIG. 2).

When the yarn is redirected from a winding station having a fully wound spool to the other yarn winding station associated with the same yarn delivery station but having an empty spool, then at that moment the spindle that carries the empty spool is driven with a standby rpm which corresponds to the rpm necessary to obtain the approximate required yarn tension when winding on the empty spool. This standby rpm which is the maximum spindle rpm in any determined 'rpm range, is set uniformly for all spindles by adjusting a frequency converter 60 (FIG. 2) to a correspondingly high frequency. It has been found in practice that the frequency converter is expediently designed in such a manner that the frequency of a voltage applied to a secondary circuit incorporated in the textile machine, should be adjustable within an appropriate range, for example, between 100 and 250 cycles. The frequency converter 60 includes a DC motor 48 which is connected to a usual primary circuit or power line 41 of, for example, 50 cycles through a switch 64 and a thyristor setting member 43. The DC motor 48 drives a three-phase generator 45 through a rigid coupling. By setting the rpm of the motor 48 by means of a regulator 69 associated with thyristor 43, the frequency applied to the secondary circuit 61 (which in this embodiment is a three-conductor bus bar) may be determined.

With each yarn delivery station 11 of the textile machine there is associated a separate yarn tension meter 22 and a yarn tension regulator 44, so that at each momentarily operational yarn winding station 12 or 13, the yarn tension of the wound yarn is automatically regulated independently from the other yarn winding stations. The output of each yarn tension meter 22 is compared with an associated desired value indicator 42 and the difference between the actual value and the desired value, which is formed at 63, is applied to the regulator 44. The output of each regulator 44 controls the firing moment of an associated thyristor setting member 50, so that by affecting the rpm of the associated drive motor in this manner, the deviation in the control is decreased. What the thyristor setting member 50 in fact does, is to lower the average value of the voltage applied to the drive motor. In this manner, the rpm of the latter is decreased.

"The two spindle drive motors 31, 31' of the spindles 33, 33' associated with a common yarn delivery station 11 are connected by a common switching device 51 to the secondary circuit 61. With the two drive motors 31,

31 there is associated a single thyristor setting member 50, which, for the purpose of decreasing the voltage applied from a'line'to the drive motors, may be of any structure suitable, as known by itself, for the rpmcontrol of asynchronous motors. For example, the thyristor setting member 50 may have for each phase of the secondary circuit two antiparallel connected thy- I ristors. By changing the firing moments of the lastnamed thyristors, the rpm of the drive motors 31, 3l

may be decreased through a wide rpm range. Or, by means of alternating complete transmission and complete blocking of the current, the thyristors may effect the energization and de-energization of the drive mo a... a A

maintained with only very small oscillations. lt has been found that in textile machines of the type under consideration, it is usually sufficient if the rpm setting range of the thyristor setting member 50 is 3:1 downwardly.

It is noted that instead of controlling the spindle rpm as a function of the yarn tension as described above, it is feasible to associate the thyristor setting members 50 during the winding operation with a programming device that operates as a function of the winding time or the diameter of the wound package.

Turning now to FIG. 3, each switching device 51 comprises four switches 53-56 movable simultaneously by means of an actuating device 52, 57 from their positions shown into an opposed position and back. In the shown position of the switching device 51, the drive motor 31 is directly connected to the secondary circuit 61 (switch 54 is open and switch 55 is closed), whereas the drive motor 31' is connected to the secondary circuit 61 through the thyristor setting member 50 (switch 56 is closed and switch 53 is open). in the other switching position of device 51, the switches 53-56 are in a reverse position so that the thyristor setting member 50 is then connected to the drive motor 31, whereas the other drive motor 31 is directly coupled to the secondary circuit 61.

Between the switching device 51 and each drive motor 31, 31' there is connected an On-Off switch 59 to disconnect the associated drive motor from the secondary circuit, for example, for the purpose of exchanging spools in the winding station.

The actuating device 52 of the switching device 51 may be connected with the deflector head 24 associated with the yarn winding stations in such a manner that simultaneously with the switching of the device 51 the deflector head 24 also changes position.

OPERATlON OF THE PREFERRED EMBODIMENT With each yarn delivery station 11 of the textile machine there are associated two yarn winding stations 12 and 13. During operation, the yarn 15' taken from a yarn delivery station 11 is wound alternately on the spindles of the two yarn winding stations so that a continuous yarn feed is possible without interruption and without loss of yarn. If one spool is completed, then, by means of the deflector head 24 and the switching device 51, the yarn is redirected to the other spindle on which, by that time, there is inserted an empty spool. By the time the switching operation occurs, the lastnamed spindle is rotated with a standby rpm. This is achieved by connecting the associated drive motor directly to the secondary circuit 61 so that the total voltage thereof is applied to this drive motor. The yarn redirected into the newly activated yarn outlet channel is automatically positioned on the empty spool of the associated yarn winding station and in this manner a new winding operation is started. At the same time, the switch 51 switches over to the regulated rpm control of the drive motor associated with the newly activated spindle by interrupting the direct connection between said drive motor and the secondary circuit 61 and connecting said drive motor to the thyristor setting member 50 and the regulator 44. The other spindle, the spool of which contains a fully wound package, is, during the above-described switching operation, directly connected to the secondary circuit 61 and is thus driven thereafter with the standby rpm. In order to replace the fully wound spool by an empty spool, the

motor of the associated spindle may be disconnected from the secondary circuit by operating the switch 59 and the spindle may be arrested in its rotation. After the empty spool is inserted, the switch 59 is closed and the spindle is again driven with the standby rpm and is thus instantaneously ready to take over the winding function, should yarn breakage occur.

The shaft of the spindle may be directly force-fitted into the rotor of the associated drive motor, or may be connected therewith in any desired manner.

Since redirecting of the yarn from the fully wound spool to the empty spool occurs in a fraction of a second, the empty spool should then rotate with the standby rpm which corresponds at least approximately to the rpm that is obtained immediately after switching the rotating empty spool over to the regulated rpm control. Since all empty spools have identical diameters and all other yarn winding conditions are identical, the standby rpms are of identical magnitude for each spindle and may thus be commonly set for all spindles by a proper adjustment of frequency of the secondary circuit. With respect to spindles which are momentarily operational (i.e., on which yarn is wound), the spindle rpms should be adapted to the existing winding conditions. Since the latter are, at any given time different for each operational spindle, the spindle rpms are regulated independently from one another. This is achieved by means of the afore-described thyristor setting members and the yarn tension regulators 44 associated therewith. The number of the thyristor setting members with the associated regulators and yarn tension meters corresponds to the number of the yarn delivery stations and thus, to half the number of the total verter with a thyristor setting member makes possible in a simple and inexpensive structure an optimal adaptation of the spindle driving means to all the different conditions encountered in practice.

It is to be understood that the afore-described embodiment is given merely by way of example and that numerous modifications thereto are possible without departing from the scope of the invention defined in the appended claim.

What is claimed is:

1. In a method of driving spindles of a textile machine being of the type which has a plurality of yarn delivery stations and a winding station spindle pair associated with each yarn delivery station, each spindle being provided with its own variable rpm drive motor, during any operational period one spindle of said spindle pair being the winding spindle on which a yarn package is being formed, while simultaneously the other spindle of the same spindle pair being the idling spindle, the role of these two spindles being exchanged upon redirecting the yarn from one spindle to the other, the improvement comprising the steps of:

A. driving the idling spindle at a maximum given standby rpm during all operating periods for the purpose of allowing the idling spindle to take over the winding function upon the occurrence of yarn 3,884,031 7 8 breakage during winding on the winding spindle; whereby the idling spindle is ready to take over the and winding function without delay at all operating B. driving the winding spindle with a decreasing rpm times including times of yarn breakage.

as a function of winding parameters; 

1. In a method of driving spindles of a textile machine being of the type which has a plurality of yarn delivery stations and a winding station spindle pair associated with each yarn delivery station, each spindle being provided with its own variable rpm drive motor, during any operational period one spindle of said spindle pair being the winding spindle on which a yarn package is being formed, while simultaneously the other spindle of the same spindle pair being the idling spindle, the role of these two spindles being exchanged upon redirecting the yarn from one spindle to the other, the improvement comprising the steps of: A. driving the idling spindle at a maximum given standby rpm during all operating periods for the purpose of allowing the idling spindle to take over the winding function upon the occurrence of yarn breakage during winding on the winding spindle; and B. driving the winding spindle with a decreasing rpm as a function of winding parameters; whereby the idling spindle is ready to take over the winding function without delay at all operating times including times of yarn breakage. 